The American's withdrawal allows Coco Vandeweghe entry as a lucky loser.
"The IOC has completely punted," Hall of Famer Martina Navratilova said.
The 2022 Wimbledon draws are out.
The US Open has stepped up its commitment to junior tennis significantly.
The Frenchman also missed Roland-Garros but is hopeful about the summer.
The qualifying draws are set in time for the singles draws on Friday.
Rafael Nadal and Matteo Berrettini did the honors on Thursdsay.
